Deep and dark, the Mud Hole is the Hudson River's channel from a time when the oceans were much lower. Today it collects all the silt and sediment that the river carries out to the sea, making it a very fertile fishing ground, frequented by pelagic fishes and sharks. The contour shown on the chart is not any particular depth, but do give an idea of the location.
This site on the Shark River Artificial Reef consists of two long ridges of seven huge rock piles each, with one long valley east-west between them. Between piles, there are smaller valleys. Each ridge contains approximately two million tons ( or one million cubic yards ) of granite, blasted and dredged from the bottom of New York harbor between September 2002 and September 2003. Peak depths range from 85 to 105 ft, bottom depth is 130 ft. In addition, 15 Redbird subway cars were deposited on or near one of the piles. A similar rockpile is located in shallower water on the Axel Carlson Reef.